Compare each included study against every protocol criterion to find the specific mismatch, then either revise the criteria with documented justification or exclude the study.
Find the mismatch first
A conflict usually traces to one criterion: a population definition, an intervention variant, a comparator, an outcome, a date limit, or a study design. Check the study against each criterion separately so you can name the exact field that fails. A study that meets five of six criteria has a specific, describable gap; a study that fails several may simply belong outside the review.
Decide between revision and exclusion
- Identify the failing criterion and quote the study detail that fails it. Expected result: a written statement of the mismatch that a co-reviewer can check against the paper.
- Judge whether the criterion was mis-specified for the review question. If the criterion excluded studies that genuinely answer the question, revise it and record the reason and the date of the change. Expected result: an amended protocol entry with a justification.
- If the study falls outside the question the review is answering, exclude it and record the exclusion reason. Expected result: a documented exclusion that matches the review's scope.
- Apply the same decision to every study with the same mismatch, so the criteria stay consistent across the set. Expected result: uniform treatment of comparable studies.
- Update the flow diagram and the methods text to reflect the final counts and any criteria changes. Expected result: reported numbers that match the included set.
Keep the record transparent
PRISMA 2020 provides a checklist and flow diagrams for transparent reporting of why a review was done, what methods were used, and what studies were found and included. Use that structure to report any criteria revision alongside the final included studies, so readers can see what changed and why. The Cochrane Handbook's guidance on searching for and selecting studies covers documenting searches and managing records, which supports keeping the decision trail attached to each study record.
Watch for indirectness
When a study meets revised criteria but differs from the review question in population, intervention, or setting, note that difference. The Cochrane Handbook's guidance on interpreting results addresses applicability and indirectness, so flag such studies in the synthesis and in how conclusions are framed.